Many styles of sportsfishing involve a technique called trolling. In this form of sportsfishing, a fishing line rigged with either artificial or natural baits is trailed behind a moving boat or launch. A natural or artificial bait is moved through the water along with the moving boat in order to cover a large territory in a body of water and thereby improve the chances of encountering fish, either singly or in schools. Also, the artificial or natural bait is moved through the water using this trolling technique in order to cause the lure to move in a fashion which will attract foraging fish.
When using the trolling technique, a fishing rod and reel are normally used to extend fishing line for some distance into the water. The line which may be braided or monofilament line of various compositions is rigged with other equipment such as leaders, weights and the like. In the case where fabric lines are used to catch predatory fish having sharp teeth, a leader is frequently attached to the end of the line. Typically, an artificial bait or artificial lure is then attached to this leader so that if a fish strikes the lure, the sharp teeth of the striking fish will not sever the line before the fish can be brought to the boat by the angler.
Trolling is a fishing technique which is used extensively to fish at the surface of the water and also to fish much deeper for species of fish which normally forage at great depths in salt and freshwater bodies of water. Lake trout are an example of a freshwater species which forage at great depths which can range to 60 feet or more from the surface. Lake trout fishing using the trolling technique is frequently practiced on the Great Lakes, such as Lake Superior, Lake Michigan and in other deep, freshwater lakes.
A number of species of ocean fish such as marlin, shark, dolphin and similar species of fish are considered "deep sea" species which are likewise caught in relatively deep water. These species are frequently the subject of sportsfishing known as deep-sea fishing.
When the trolling technique is used for deep-sea fishing or for fishing lake trout and similar species of deep foraging fresh water fish, a device known as a downrigger is employed in order to sink the fishing lure to a depth where the particular fish species is foraging. This downrigger is essentially a winch, boom and pulley arrangement using a length of relatively strong line to which a heavy weight has been added. The downrigger normally employs a very strong rod and reel combination or a boom and winch which drops a strong line frequently made of copper wire to the depth desired. A heavy weight, frequently weighing as much as ten pounds, is attached to the downrigger line or cable to force the cable to the depth desired. The downrigger weight has a line release to which a fishing line having a lure is attached so that as the downrigger weight is lowered, it sinks the fishing line and lure to the depth where the deepwater fish are foraging.
Sportsfishing boats often use several downriggers to extend several fishing lines which, when dragged behind a moving boat, have a tendency to become entangled. This tendency to become entangled is apparent because there is a limited amount of room at the rear of a fishing boat for placing the fishing rigs in the water. Frequently, a boat will only employ two rods and reels when trolling. One is positioned at either corner of the rear of the boat. This limits the number of lures which can be trailed behind the fishing boat and thereby limits the opportunities for attractive foraging fish.
Limitations on the number of lures which can be trailed behind a boat places severe limitations on the number of clients which a fishing boat operator may place on board his boat for the purpose of enjoying deep-sea fishing If the number of lines used is too great, the lines will constantly become entangled and thereby reduce the enjoyment and opportunity for catching fish.
One technique to overcome this limitation on the number of lures trailed behind a trolling boat is to employ a rig mounted high on an elevated bridge of the boat. Elevated mounts hold additional lines away from lines which are extended from the rear of the boat. This technique is marginally successful since the lines connected to the rigging still tend to trail directly behind the boat when it is moving. Consequently, such rigging is still subject to entanglement. Such riggings normally do not tend to separate the trolling lures horizontally from each other in order to avoid entanglement. Consequently, there are severe limitations on the number of fishing lines which can be extended from a boat which is trolling for deep-water species of fish.